Software Engineer, Fullstack (UK)
Confirmed on the employer's own hiring board on Oct 25, 2026. First seen by Alion on Jun 3, 2026.
Job Summary
The Software Engineer will join the team responsible for Firstup's public APIs, Agentic tools, third-party integrations with enterprise systems such as HRIS platforms, and shared platform services. You will deliver innovative, scalable solutions while constantly improving our approach to architecture, scale, availability, and fault-tolerance. You are an active user of Generative AI tools and coding agents, applying them daily to accelerate delivery and improve code quality.
Responsibilities
Contribute to the design, development, and maintenance of public-facing APIs used by enterprise customers.
Build and maintain integrations with external enterprise systems, including HRIS platforms such as Workday, SAP SuccessFactors, and Dayforce.
Support shared platform services used across the engineering organisation.
Write clean, well-tested, and well-documented code, and participate in code reviews.
Work within large-scale multi-tenant cloud services, developing your understanding of scalability and fault-tolerance.
Use Generative AI tools and coding agents in day-to-day workflows to improve code quality and delivery speed.
Collaborate with teammates and cross-functional partners to solve problems and deliver customer value.
Contribute to production health, including on-call rotations and incident response, in a "you build it, you run it" environment.
Identify and help resolve availability, reliability, and performance issues.
Minimum Qualifications
Bachelor's degree in Computer Science or related field, or equivalent experience.
3-5 years building reliable, performant applications and microservices.
Proficiency in TypeScript and Node.js. Ruby experience is a plus.
Experience across frontend (React.js), backend, and database layers.
AWS experience, including core compute, storage, and networking services.
Curiosity, a desire to learn, and openness to feedback.
A focus on customer experience in the work you deliver.
Preferred Qualifications:
Experience with HRIS integrations, such as Workday, SAP SuccessFactors, Dayforce, or similar platforms.
Experience with Kubernetes, Docker, and Helm.
Familiarity with Datadog or similar observability and monitoring platforms.
Demonstrated use of Generative AI tools or coding agents in development workflows.
Experience in enterprise SaaS organisations.
Open-source contributions or a history of side projects.